T-rays: New Imaging Technology

An adaptable technology that can detect cracks in space shuttle foam, in addition to also offering the potential to see biological agents through a sealed envelope and detect tumors without harmful radiation, was recently discussed at a symposium at the annual meeting of the American Chemical Society, held in Washington, DC, USA in August 2005.

The session was co-chaired by T-ray specialists Dr. Xi-Cheng Zhang, a physicist and engineer at Rensselaer Polytechnic Institute (Troy, NY, USA), and Dr. Charles Schmuttenmaer, a chemist at Yale University (New Haven, CT, USA). T-rays are the next-generation development in imaging and sensing technology. Based on the terahertz (THz) region of the electromagnetic spectrum, defined by frequencies from 0.1-10 THz (just between infrared light and microwave radiation), T-rays may have potential for a wide variety of applications.

Objects at room temperature emit thermal energy in the THz range. This radiation is very useful for sensing and imaging objects, with significant advantages over other methods, according to Dr. Zhang. T-ray systems provide more than just images: they can offer valuable spectroscopic information about the composition of a compound, particularly in chemical and biological species--something that x-rays may not be able to do. T-rays are also safer than x-rays for biologic applications, according to Dr. Zhang, with photon energies that are one million times weaker than x-ray photons.

Until recently, scientists have had great difficulty controlling the potential of the THz region, mainly because of a scarcity of appropriate radiation sources. Dr. Zhang reported that new developments achieved at Rensselaer has allowed for the sensing of extremely small objects on the nanometer scale, as well as at large distances of more than 100 meters--an essential improvement for national security applications such as remote sensing of explosives. He has also collaborated with U.S. National Aeronautics Space Administration (NASA) with this technology, where THz imaging successfully detected defects in space shuttle foam.

T-ray applications could enable the label-free characterization of genetic material, identify a C-4 explosive hidden in the mail, and help scientists understand the complicated dynamics involved in protein folding, according to the researchers.






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